1. Field of the Invention
The present invention relates to a method of producing composite strips composed of an aluminum core coated on one face or on both faces with a metal having a melting point and mechanical strength which are substantially higher than those of aluminum by casting the aluminum continuously between rolls and interposing a metal plating strip between the work roll or rolls and the aluminum. The invention also relates to the composite strips obtained by such a method.
2. Description of the Prior Art
French Pat. No. 1,364,758, granted on 19th May, 1964, describes in principle a continuous casting method in which the still liquid metal is introduced between two cooled rolls and in which a metal plating strip is interposed between this liquid metal and the work rolls, this metal plating strip being entrained continuously with the rolled metal and thus being plated onto it. The purpose of this process was essentially to plate an aluminum blank, whose surface exhibited a fairly coarse texture due to the small amount of working, with a strip of aluminum having an improved resistance to corrosion and a surface condition which is of better quality or which is more suitable, in particular, for anodic oxidation treatment or polishing treatment. However, the information given in said patent does not allow plating to be performed with a metal having properties which are quite different from those of aluminum, for example, plating with stainless steel to give sufficient adhesion for the composite strip subsequently to be transformed.
Various methods for the continuous casting of aluminum between rolls are also known. For example, French Pat. No. 1,198,006 granted on 8th June, 1959, as well as its Certificate of Addition No. 74839, describe a device comprising a supply tank which receives the molten metal from a casting furnace and a nozzle having a flattened profile which is intended to distribute the metal over a strip of given width. The end of the nozzle is fitted between two parallel rolls which are spaced apart. The molten metal leaving the nozzle cools and solidifies upon contact with the cooled rolls and is entrained in the form of a strip which is subjected to a certain pressure, due to the curvature of the rolls. Once it has reached the plane of the roll axes, the strip is wound onto a winder. That method permits the production of aluminum strips in a range of thicknesses of from 1.5 mm to 20 mm thick in an economical manner. The prior processes do not provide composites producable according to the present invention.